Resinous compositions containing butadiene-1, 3 and polyalkylpyridines and process of preparing them



United States Patent '0 RESINOUS COMPOSITIONS CONTAINING 'BUTA- DIENE-LBAND POLYALKYLPYRIDINES .AND PROCESS OF PREPARING THEM No Drawing.Application September 7, 1954 Serial No. 454,609

8 Claims. (Cl. 260-942) This invention relates to synthetic polymerscontaining a pyridine ring in their molecular make-up and to the processof preparing them. More particularly, it relates to polymers prepared bythe interaction of polyalkylpyridines with conjugated dienes.

In U. S. Patent 2,402,020 there are described various elastomerscontaining pyridine rings in their molecular structure. The elastomersdescribed therein are prepared by the copolymerization of vinylpyridinewith various monomers, such as butadiene, styrene, acrylonitrile, andthe like. Subsequent to the granting of the above patent, many otherpatents were issued to various inventors relating to vinylpyridinecopolymers. Today, vinylpyridine copolymers are widely used in therubber industry, in the synthetic fiber industry, for the manufacture ofphotographic film, etc. Because of their unique properties, theycontinue to find more uses in spite of their relatively high price.

I found that I can prepare polymers containing the pyridine nucleus byreacting a polyalkylpyridine, such, for example, as 2,6-lutidine, with aconjugated diene as, for example, 1:3-butadiene. The condensation of thepolyalkylpyridine and the conjugated diene is brought about by alkalimetals as, for example, sodium.

The polyalkylpyridines which are particularly useful for practicing myinvention are 2,6-lutidine, 2,4,6-collidine, 2,4-lutidine,2-methyl-4-ethylpyridine, 2,6 diethylpyridine. All of these pyridinesare characterized by the presence of a CH grouping in the 2- positionand in either or both the 4- position, and the 6- position. I prefer touse the polyalkylpyridines which have a -CH grouping in those positionsbecause of their greater reactivity, but I may use any polyalkylpyridinehaving at least two -CH groupings attached to the pyridine nucleus.

For economic reasons I prefer to use 1:3-butadiene for copolymerizationwith the polyalkylpyridines. I may, however, use other conjugateddienes, such for example, as isoprene or 2,3-dimethylbutadiene.

The examples cited below are illustrative of the manner in which myinvention may be practiced:

Example 1 A mixture of two moles of 2,6-lutidine, four moles of1:3-butadiene and /3 mole of sodium is prepared in a pressure vesselequipped with an agitator. The mixture is heated, under pressure, to atemperature of from about 100120 C.; it is agitated continually. Theinteraction ot: the 2,6-lutidine and the butadiene generates sufficientheat to maintain the reaction mixture at this temperature. As thereaction proceeds, the pressure in the vessel gradually drops and thereaction is considered complete when the pressure falls to nearatmospheric. The mixture is then cooled and any residual pressure isreleased. Then, about one mole of methanol or water is added to kill thesodium. The resultant mixture is then subjected to distillation undervacuum to remove unreacted 2,6-1utidine, butadiene, and other volatileprod- 2,8265% Patented Mar. 11., .1958

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acts. The =copol-ymer of 2;6-lutiiiine and "butadiene remains as adistillation residue in the reaction vessel and is removed therefromwhile still hot. 'The copolymer is allowed to ;cool in shallow ,pans.

flzhe 1 presence :of the pyridine ring nitrogen; in the resin moleculemakes it "particularlyuareceptive of .dyes. The incorporation of thisresin in the melt used to spin polyacrylonitrile fibers enhances thedyeing properties of these fibers, commercially known as Orion, Acrilan,and Dynel.

In place of using sodium, I may use other alkali metals, or I may usesodio-2,6-lutidine made by the reaction of 2,6-lutidine and sodamide.

The ratio of 2,6-lutidine to butadiene may be varied widely; the lowerthe ratio, the more elastic the copoly-- mer.

More rigid copolymers may be formed. by reacting 2,4,6-collidine withbutadiene. These may be formed in accordance with Example 2. 1

Example 2 Three moles of 1:3-butadiene are cooled to about 0 C. To thiscold butadiene there is gradually added one mole of a mixture composedof 2,4,6-collidine and 25% of sodio-2,4,6-collidine (made by reactingsodamide with 2,4,6-collidine) The temperature of the reaction mixtureis maintained at about 0 C. After all of the sodiocollidine-collidinemixture has been added, the temperature of the reaction mixture isallowed to rise gradually until a temperature of about 30 C. is reached.It is held at this temperature for about two hours. Then, thetemperature is raised to about C. The sodium is killed with methanol andthe mixture subjected to vacuum distillation to remove the volatilematerials present. The residue is the desired copolymer of2,4,6-collidine and lz3-butadiene. It is removed from the reactionvessel and is cooled in shallow pans.

The 2,4,6-collidine-butadiene copolymers are useful in the preparationof metal protecting paints. The pyridine ring nitrogen in the resinmatrix seems to be responsible for the strong afiinity of thesecopolymers for metals.

Example 3 The process of Example 1 and of Example 2 is repeated savethat 2,4-lutidine is used in place of the 2,6- lutidine of Example 1 andin place of the 2,4,6-collidine of Example 2.

In general, I prefer to copolymerize an individual polyalkylpyridinewith a diene. However, if I so desire, I may copolymerize a mixture ofpolyalkylpyridines with a diene. For instance, in the synthesis ofpicolines from acetylene and ammonia there is obtained a by-product ofpolyalkylpyridines having a distillation range of from ISO- C. Such amixture when copolymerized with butadiene yields a copolymer which isefifective for inhibiting the action of dilute sulfuric acid on steel.

I claim as my invention:

1. The process of making a resinous composition which comprises reactinga conjugated butadiene with a pyridine compound of the class consistingof 2,6-1utidine, 2,4,6- collidine, and 2,4-lutidine.

2. The process of making a resinous composition which comprises reactinga mixture of 1:3-butadiene, sodium, and a compound of the classconsisting of 2,6- lutidine, 2,4,6-co1lidine, and 2,4-lutidine andrecovering the resultant copolymer.

3. The process of making a resinous composition which comprises reactinga mixture of 2,4,6-collidine, 1:3- butadiene, andsodio-2,4,6-coll.idine.

4. The process of making a resinous composition which comprises mixing1:3-butadiene with a compound of the class consisting of 2,6-lutidine,2,4,6-collidine, and 2,4- lutidine and mixtures thereof and with acompound sea w o W A lected from the group consisting of sodium,sodio-2,6- 8. The product obtained by the process of claim 2 inlutidine, sodio'-2,4,6-collidine, and sodio-2,4-lutidine, which the PyCompound used is 24'111tidimheating the resultant mixture under pressureto cause polymerization and recovering the resultant resinous ReferencesCited m the file of thls patent rproductt 5 UNITED STATES PATENTS 5. Theproduct obtained by the process of claim 1. 2,549,651 W i b Apr, 17,1951 6. The product obtained by the process of claim 2. 2,640,042How1and et a] May 16, 1953 7. The product obtained by the process ofclaim 2 2,670,390 Pines et a1. Feb. 23, 1954 in which the pyridinecompound used is 2,6-1utidine. 2,746,943 Pritchard May 22, 19 56

1. THE PROCESS OF MAKING A RESINOUS COMPOSITION WHICH COMPRISES REACTINGA CONJUGATED BUTADIENE WITH A PYRIDINE COMPOUND OF THE CLASS CONSISTINGOF 2,6-LUTIDINE, 2,4,6COLLIDINE, AND 2,4-LUTIDINE.